Messages in this thread | | | Subject | Re: [RFC/RFT PATCH v3] sched: automated per tty task groups | From | Peter Zijlstra <> | Date | Fri, 19 Nov 2010 12:57:24 +0100 |
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On Fri, 2010-11-19 at 01:07 +0100, Samuel Thibault wrote: > > > Also note that having a hierarchical process structure should permit to > make things globally more efficient: avoid putting e.g. your cpp, cc1, > and asm processes at three corners of your 4-socket NUMA machine :)
We have the hierarchy mandated by POSIX to track parents, childs, sessions and all that stuff, its just not the data structure used for scheduling.
And no, using that to load-balance between CPUs doesn't necessarily help with the NUMA case, load-balancing is an impossible job (equivalent to page-replacement -- you simply don't know the future), applications simply do wildly weird stuff.
From a process hierarchy there's absolutely no difference between a cc1/cpp/asm and some MPI jobs, both can be parent-child relations with pipes between, some just run short and have data affinity, others run long and don't have any.
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